Image optimization

The BlackBerry® MDS Connection Service and the BlackBerry Internet Service Browsing network gateways check the physical characteristics of the destination BlackBerry device, and scale the image and reduce the color depth as appropriate.

Property

Description

image size

To reduce the use of bandwidth and improve display, the network gateway scales images. When the network gateway delivers content for display in Page View, the network gateway scales images proportionally with the content.

When the network gateway delivers content for display in Column View, the network gateway scales images in the following ways:
  • Horizontal scaling: Images are scaled to fit the width of the BlackBerry device screen, less 5 pixels for the scrollbar.
  • Vertical scaling: Images are scaled to a maximum height of twice the screen height.

The network gateway maintains the aspect ratio when it scales images.

Users can download the full image. The BlackBerry® Browser sends a secondary request to the network gateway to deliver the image in its original form, with no optimization.

image color depth

The BlackBerry MDS Connection Service and the BlackBerry Internet Service Browsing network gateways reduce the color depth of the image to match the number of colors that the destination BlackBerry device supports. This results in smaller file sizes and minimizes the use of bandwidth.

Enhanced image optimization is included in the BlackBerry MDS Connection Service network gateway (version 4.1.3 or later) and the BlackBerry Internet Service Browsing network gateway. Enhanced image optimization is designed to provide an additional 15 to 20% size reduction. Higher quality images can be sent to the BlackBerry device without an increase in the use of bandwidth. Enhanced image optimization applies only to GIF, PNG, and JPEG image formats.

Users with BlackBerry devices running BlackBerry® Device Software version 4.2.1 or later can specify the level of quality as low, medium, or high for images sent to the BlackBerry device. For BlackBerry devices running earlier versions of the BlackBerry Device Software, the network gateway sets the image quality as medium.

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